Review on the Bubble Dynamics Based Cavitation Dynamics for the Negative Squeeze Motion in Lubricated Contacts

Abstract

Simulation models for the cavitation dynamics in lubricated contacts can be roughly clustered into two groups: either without or with bubble dynamics, the first one being the standard case for most fluid film bearing calculations. The approach with bubble dynamics has been introduced to the lubrication community about 20 years ago by Someya, and it is based on the coupling of Reynolds equation and Rayleigh-Plesset equation. It has been used for journal bearings, squeeze film dampers, and it is essentially required for correct numerical calculations of the negative squeeze motion (i.e., the separation of two plates) or the oil stiction problem. More than a decade ago, in 2009, the first paper on the negative squeeze motion with bubble dynamics-allowing numerical calculations of tensile stresses in the lubricant-had been published. The application in mind is the simulation of mixed lubrication for rough surfaces. The negative squeeze motion is then understood as the motion of asperities (on smaller length scales). The paper at hand summarizes some of the research on the dynamics of cavitation in lubricated contacts from different research groups from the last 10-15 years and sketches key topics for further research on the topic. The roadmap is centered around the three key issues that remained from the previous research of the author: (a) numerical stability of the calculations for curved plates, (b) characteristic time scale for separation of plates, and (c) experimental evidence for validating the calculation results.

A new method to solve the Reynolds equation including mass-conserving cavitation by physics informed neural networks (PINNs) with both soft and hard constraints

“…1) It is difficult to consider the discontinuity film height conditions, but they can also be found in practice, such as for pocket bearings [4,6] and the textured journal bearings [25]. Due to the non-differentiable nature at the discontinuity points, we cannot employ the PINNs method to obtain the solutions directly.…”

“…For the cavitation research there are still some open questions, such as the effects of the micro-jet and the shockwave caused by the cavitation on the pitting [1]. In this work we focus on the cavitation in lubrication, and extensive papers on this topic for both numerical and experimental ways can be found, and the reader is referred to the reviews of Dowson et al [2], Braun et al [3], Geike [4], and Kamat et al [5] For analyzing the lubrication problems, the Reynolds equation has been widely used, but the effects of cavitation are not considered in it. In order to analyze the film pressure behaviors with the cavitation effects, attempts have been made by many researchers and different cavitation models have been developed [6].…”

Bubble Dynamics-Based Modeling of the Cavitation Dynamics in Lubricated Contacts

“…An overview of research results on the simulation of cavitation dynamics can be found in the publications [2,3]. There is one common feature of all simulations known to the author: they do not reproduce the fine spatial structures as observed in experiments.…”

“…The original model of the author yielded qualitatively reasonable results, but three key issues remained [3].…”